Keccis Medical Service

 If pathogens are to be isolated successfully, the type of specimen, its collection time, and method of its dispatch to the laboratorty must be correct.  Adequate information about the patient’s condition and antimicrobial treatment must also be sent in the Specimen. Type of specimen The correct type of specimen to be collected will depend on the pathogens to be isolated as follows; SPUTUM Possible pathogens BACTERIA Also Mycobacterium tuberculosis , Mycoplasma pneumoniae , and Legionella pneumophila FUNGI AND ACTINOMYCETES Pneumocystis jiroveci, Blastomyces dermatitidis, Histoplasma capsulatum, Aspergillus species, Candida albicans, Cryptococcus neoformans, and Nocardia species. PARASITES Paragonimus species Commensals Sputum as it is being collected passes through the pharynx and the mouth. It therefore becomes contaminated with small numbers of commensal organisms from the upper respiratory tract and mouth. These include; BACTERIA THROAT AND MOUTH SPE...

Morphological classification of medical important bacteria Morphologically bacteria can resemble: Cocci (Singular: coccus) Bacilli / rods (Singular: rod, bacillus) Vibrios (Singular: vibrio) Spirilla (Singular: spirillum) Spirochaetes (Singular: spirochaet Cocci : These are round or oval bacteria measuring about 0.5–1.0 m in diameter. When multiplying, cocci may form pairs, chains, or irregular groups:   cocci in pairs are called diplococci, e.g. meningococci and gonococci. cocci in chains are called streptococci, e.g. Streptococcus pyogenes. cocci in irregular groups are called staphylococci, e.g. Staphylococcus aureus. Gram reaction : Staphylococci and streptococci are Gram positive, whereas diplococci can be Gram positive or Gram negative. Rods (bacilli): These are stick-like bacteria with rounded, tapered (fusiform), square, or swollen ends. They measure 1–10 µ m in length by 0.3–1.0 µ m in width. The short rods with rounded ends are often called coccobacilli. When mul...

What is Gram Staining? Gram staining is a common technique used to differentiate two large groups of bacteria based on their different cell wall constituents. The Gram stain procedure distinguishes between Gram positive and Gram negative groups by coloring these cells red or violet. Gram positive bacteria stain violet due to the presence of a thick layer of peptidoglycan in their cell walls, which retains the crystal violet these cells are stained with. Alternatively, Gram negative bacteria stain red, which is attributed to a thinner peptidoglycan wall, which does not retain the crystal violet during the decoloring process. How Does Gram Staining Work? Gram staining involves three processes: staining with a water-soluble dye called crystal violet, decolorization, and counterstaining, usually with safanin. Due to differences in the thickness of a peptidoglycan layer in the cell membrane between Gram positive and Gram negative bacteria, Gram positive bacteria (with a thicker pept...